CN111771289B

CN111771289B - Light emitting device and capacitor

Info

Publication number: CN111771289B
Application number: CN201980015812.4A
Authority: CN
Inventors: 泷本直美; 松冈高广; 串间贵仁; 大原达也; 安藤翔太; 中野浩之
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2018-04-26
Filing date: 2019-02-25
Publication date: 2023-09-05
Anticipated expiration: 2039-02-25
Also published as: JPWO2019207938A1; CN111771289A; US20210028158A1; US11652092B2; JP6912000B2; DE112019002158T5; WO2019207938A1

Abstract

The invention provides a light emitting device capable of realizing short pulse of output light. A light emitting device (100) of the present invention comprises: a capacitor (10); one or more solid state light emitting elements (20) that emit light by being supplied with power from the capacitor (10); and a semiconductor switch (30) for controlling the power supply from the capacitor (10) to the solid state light emitting element (20). Further, a solid state light emitting element (20) is placed on the outer surface of the capacitor (10), and a semiconductor switch (30) is placed on the outer surface of the capacitor (10) or is provided inside the capacitor (10), and the capacitor (10) has a connection electrode (32) for connecting the solid state light emitting element (20) and the semiconductor switch (30) in series between the external electrodes (11, 12).

Description

Light emitting device and capacitor

Technical Field

The present invention relates to a light-emitting device including one or more solid-state light-emitting elements, and a capacitor on which one or more solid-state light-emitting elements can be mounted.

Background

In recent years, liDAR (Light Detection and Ranging: light detection and ranging) has been used in automobile systems, weather-observing systems, and the like. The LiDAR includes a light-emitting device including a laser diode, a semiconductor switch, a clamp diode, a power supply capacitor, and the like as described in non-patent document 1.

The driving method of the light emitting device includes a capacitor discharge method and a switching control method. In a light emitting device employing a capacitive discharge method, light having a pulse width is generated from a laser diode by resonance between parasitic inductance and a power supply capacitor. On the other hand, in a light emitting device employing a switching control system, on/off of a laser diode is controlled to generate light having a pulse width by controlling on/off of a semiconductor switch.

Non-patent document 1: john glass, "How GaN Power Transistors Drive High-Performance Lidar: generating ultrafast pulsed power with GaN FETs", IEEE Power Electronics Magazine, US, march 2017, p.25-35

However, in the light emitting device employing the capacitor discharge method as described in non-patent document 1, since the laser diode is driven at a resonance frequency determined by parasitic inductance and the capacitance of the power supply capacitor, the pulse width of the output light is fixed, and it is difficult to output light of a free pulse width.

On the other hand, in the light-emitting device employing the switching control method as described in non-patent document 1, there is a problem in that a degree of freedom is provided in the pulse width of the output light, but the parasitic inductance limits the rising speed of the current of the laser diode, and it takes a certain time or more when the required current value flows. In other words, even a light emitting device employing a switching control system can only output light having a pulse width of a predetermined or more, and cannot realize short pulse of light.

It is said that a distance resolution of several cm is required in an automotive system in order to achieve autopilot. However, in the automotive system, a LiDAR is used, and a conventional light emitting device is configured such that a laser diode, a semiconductor switch, a clamp diode, a power supply capacitor, and other components are disposed on one surface of a printed circuit board or the like. Since the distance between the components is several hundred μm, the parasitic inductance of the current loop including the laser diode during the operation of the circuit is several nH. Therefore, there is a problem that the on-time width of the light output from the light emitting device is limited to a value larger than several ns, and the distance resolution cannot be sufficiently ensured.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a light emitting device capable of shortening the pulse of light to be output, and a capacitor capable of shortening the pulse of light to be output by a solid state light emitting element to be mounted.

A light-emitting device according to an embodiment of the present invention includes: a capacitor, the capacitor comprising: a dielectric layer, a first internal electrode and a second internal electrode provided with the dielectric layer interposed therebetween, a first external electrode electrically connected to the first internal electrode, and a second external electrode electrically connected to the second internal electrode; one or more solid state light emitting elements that emit light by being supplied with power from a capacitor; and a switching element for controlling power supply from the capacitor to the solid state light emitting element, wherein the solid state light emitting element is mounted on an outer surface of the capacitor, and wherein the switching element is mounted on the outer surface of the capacitor or is provided inside the capacitor, and wherein the capacitor has a conductive portion for connecting the solid state light emitting element and the switching element in series between the first external electrode and the second external electrode.

A capacitor according to an aspect of the present invention is a capacitor including a dielectric layer, and first and second internal electrodes provided with the dielectric layer interposed therebetween, the capacitor including: a mounting part for mounting one or more solid-state light-emitting elements that emit light by supplying power from the capacitor, and a switching element that controls the power supply from the capacitor to the solid-state light-emitting elements; and a conductive portion provided in the mounting portion and connecting the capacitor and the switching element in series.

According to the present invention, the parasitic inductance can be reduced and the light output from the solid-state light-emitting element can be made into a short pulse by connecting the solid-state light-emitting element and the switching element in series and placing them on the outer surface of the capacitor.

Drawings

Fig. 1 is a schematic diagram for explaining the structure of a light-emitting device according to embodiment 1 of the present invention.

Fig. 2 is a circuit diagram of the light-emitting device according to embodiment 1 of the present invention.

Fig. 3 is a schematic diagram for explaining the structure of a light-emitting device according to embodiment 2 of the present invention.

Fig. 4 is a schematic diagram for explaining the structure of a light-emitting device according to embodiment 3 of the present invention.

Fig. 5 is a circuit diagram of a light-emitting device according to embodiment 3 of the present invention.

Fig. 6 is a schematic diagram for explaining a structure of a light-emitting device according to embodiment 4 of the present invention.

Fig. 7 is a schematic diagram for explaining a structure of another light-emitting device according to embodiment 4 of the present invention.

Fig. 8 is a schematic diagram for explaining a structure of a light-emitting device according to embodiment 5 of the present invention.

Fig. 9 is a schematic diagram for explaining a structure of a light-emitting device according to embodiment 6 of the present invention.

Fig. 10 is a schematic diagram for explaining the structure of a light-emitting device according to a modification of embodiment 6 of the present invention.

Fig. 11 is a schematic diagram for explaining a structure of a light-emitting device according to embodiment 7 of the present invention.

Fig. 12 is a schematic diagram for explaining the structure of a light-emitting device according to modification (1) of the present invention.

Fig. 13 is a schematic diagram for explaining the structure of a light-emitting device according to modification (2) of the present invention.

Fig. 14 is a schematic diagram for explaining a structure of a light-emitting device according to modification (3) of the present invention.

Fig. 15 is a schematic diagram for explaining a structure of a light-emitting device according to modification (4) of the present invention.

Fig. 16 is a schematic diagram for explaining a structure of a light-emitting device according to modification (5) of the present invention.

Fig. 17 is a circuit diagram of a light-emitting device including a driving element that drives a semiconductor switch.

Fig. 18 is a schematic diagram for explaining a structure of a light-emitting device according to a modification (10) of the present invention.

Fig. 19 is a side view of a light-emitting device according to a modification (10) of the present invention.

Fig. 20 is a schematic diagram for explaining another example of the structure of the light-emitting device according to modification (10) of the present invention.

Fig. 21 is a circuit diagram of a light-emitting device according to modification (11) of the present invention.

Fig. 22 is a schematic diagram for explaining a structure of a light-emitting device according to modification (11) of the present invention.

Fig. 23 is a side view of a light-emitting device according to a modification (11) of the present invention.

Fig. 24 is a schematic diagram for explaining another example of the structure of the light-emitting device according to modification (11) of the present invention.

Detailed Description

Hereinafter, a light emitting device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Moreover, in the figures, like reference numerals designate identical or corresponding parts.

(embodiment 1)

Hereinafter, a light-emitting device according to embodiment 1 of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram for explaining the structure of a light-emitting device 100 according to embodiment 1 of the present invention. Fig. 1 (a) shows a top view of the light emitting device 100 as seen from the outer surface of the capacitor 10 on which the solid state light emitting element 20 is mounted, and fig. 1 (b) shows a cross-sectional view on the I-I plane of the light emitting device 100.

The light-emitting device 100 shown in fig. 1 includes a capacitor 10, a solid-state light-emitting element 20 mounted on an outer surface of the capacitor 10, and a semiconductor switch 30. The capacitor 10 is a power supply capacitor and is formed of a laminated ceramic capacitor. Therefore, the capacitor 10 is alternately laminated with the plurality of internal electrodes 14, 15 for acquiring electrostatic capacitance, and the dielectric ceramic layer 13. In other words, the internal electrodes 14 (first internal electrodes) and the internal electrodes 15 (second internal electrodes) are alternately laminated with the dielectric ceramic layers 13 interposed therebetween to constitute a laminated body. The stacked internal electrodes 14, 15 are alternately led out at one end and the other end of the capacitor 10. The internal electrodes 14 and 15 led out from the respective ends are connected to the external electrodes 11 and 12 provided at the respective ends of the capacitor 10. In other words, the external electrode 11 (first external electrode) is formed at one end portion of the laminate, and the external electrode 12 (second external electrode) is formed at the other end portion of the laminate opposite to the one end portion.

The capacitor 10 can be formed by stacking a plurality of barium titanate-based ceramic green sheets (dielectric ceramic layers 13) in which an electrode pattern is formed by printing a conductive paste (Ni paste) by screen printing, for example.

Further, the capacitor 10 is also formed with external electrodes 11 and 12 on the outer surfaces of the solid-state light-emitting element 20 and the semiconductor switch 30. Specifically, in the capacitor 10 shown in fig. 1, the external electrode 11 is formed on the left side of the outer surface on the paper surface, and the external electrode 12 is formed on the right side of the outer surface on the paper surface. Further, a gate extraction electrode 31 and a connection electrode 32 are formed between the external electrodes 11 and 12 on the outer surface of the capacitor 10.

The solid state light emitting element 20 is a light emitting element that emits light by energizing a solid substance, and includes a Light Emitting Diode (LED), a Laser Diode (LD), an electroluminescent Element (EL), and the like. The solid state light emitting element 20 has a light emitting portion 22 that emits light in a direction parallel to the outer surface of the capacitor 10. Therefore, the light emitting device 100 can output light in a direction parallel to the outer surface of the capacitor 10. The solid state light emitting element 20 connects one electrode (for example, anode) with the external electrode 11, and the other electrode (for example, cathode) with the wiring 21. The wiring 21 electrically connects the solid state light emitting element 20 and the connection electrode 32. As a material of the wiring 21, au, al, cu, or the like can be used. The wiring 21 may be in the shape of an electric wire, a band, a clip, or the like.

The semiconductor switch 30 is a switching element, and for example, silicon MOSFET, gaNFET or the like can be used. The semiconductor switch 30 connects one electrode (e.g., drain electrode) with the connection electrode 32, and electrically connects the other electrode (e.g., source electrode) with the wiring 33. The gate electrode of the semiconductor switch 30 is electrically connected to a gate extraction electrode 31 formed on the outer surface of the capacitor 10. The wiring 33 electrically connects the semiconductor switch 30 with the external electrode 12. As a material of the wiring 33, au, al, cu, or the like can be used. The wiring 21 may be in the shape of an electric wire, a band, a clip, or the like.

Fig. 2 is a circuit diagram of the light-emitting device 100 according to embodiment 1 of the present invention. In the circuit diagram shown in fig. 2, one electrode of the capacitor 10 is connected to one electrode (e.g., anode) of the solid state light emitting element 20, and the other electrode (e.g., cathode) of the solid state light emitting element 20 is connected to the semiconductor switch 30. One electrode (e.g., drain electrode) of the semiconductor switch 30 is connected to the solid-state light-emitting element 20, and the other electrode (e.g., source electrode) is connected to the other electrode of the capacitor 10 and GND wiring.

In the light-emitting device 100, the solid-state light-emitting element 20 and the semiconductor switch 30 are placed on the outer surface of the capacitor 10, and the capacitor 10, the solid-state light-emitting element 20 and the semiconductor switch 30 are connected in series as shown in fig. 2 using the external electrodes 11 and 12, the wiring 21, the connection electrode 32, and the wiring 33. Here, the wiring 21 and the connection electrode 32 are conductive portions for connecting the solid-state light-emitting element 20 and the semiconductor switch 30 in series. The conductive portion shown in fig. 1 is an example, and the structure of the wiring, the electrode, and the like included may be changed according to the circuit structure and the manufacturing.

The capacitor 10 has an outer surface of the capacitor 10 as a mounting portion for mounting the solid state light emitting element 20, and a connection electrode 32 is provided on the outer surface of the capacitor 10 as a conductive portion for connecting the capacitor 10 and the semiconductor switch 30 in series.

By mounting the solid state light emitting element 20 and the semiconductor switch 30 on the outer surface of the capacitor 10, the light emitting device 100 can make the distance between the capacitor 10 and the solid state light emitting element 20 and the distance between the capacitor 10 and the semiconductor switch 30 shorter than in the conventional case of connection via wiring. In other words, as shown in fig. 1 (b) and fig. 2, the light emitting device 100 can reduce the current loop a flowing in the capacitor 10, the solid state light emitting element 20, and the semiconductor switch 30.

As shown in fig. 1 b, the direction of the current flowing through the current circuit a is opposite to and faces the direction of the current flowing through the internal electrodes 14 and 15 (arrows of solid lines) and the direction of the current flowing through the external electrodes 11 and 12 and the connection electrode 32 (arrows of broken lines). Further, the direction of the current flowing through the external electrodes 11, 12 and the connection electrode 32 (solid arrow) is opposite to the direction of the current flowing through the internal electrodes 14, 15 (broken arrow) by a distance h of the outer thickness of the capacitor 10. In other words, the current loop a can shorten the distance between the currents flowing in opposite directions to the distance h. On the other hand, in the case where the capacitor 10, the solid-state light-emitting element 20, and the semiconductor switch 30 are connected by wiring as in the prior art, the distance between the currents which face each other and flow in opposite directions is longer than the distance h.

The light emitting device 100 can reduce the parasitic inductance of the current circuit a by shortening the distance between the currents that face each other and flow in opposite directions, thereby increasing the effect of canceling each other (cancellation effect) of the magnetic fluxes. Therefore, in the case where the light-emitting device 100 employs the capacitive discharge method, since the parasitic inductance of the current loop a is small, the power supply voltage can be reduced, and the cost of the light-emitting device 100 can be reduced and miniaturized. In addition, when the light-emitting device 100 employs the switching control method, since the parasitic inductance of the current loop a is small, the pulse width of the current can be shortened, and the light output from the solid-state light-emitting element can be made into a short pulse.

As described above, the light emitting device 100 according to embodiment 1 includes the capacitor 10, and the capacitor 10 includes: a dielectric ceramic layer 13; an internal electrode 14 (first internal electrode) and an internal electrode 15 (second internal electrode) provided with the dielectric ceramic layer 13 interposed therebetween; an external electrode 11 (first external electrode) electrically connected to the internal electrode 14; and an external electrode 12 (second external electrode) electrically connected to the internal electrode 15. Further, the light-emitting device 100 includes one or more solid-state light-emitting elements 20 that emit light by supplying power from the capacitor 10, and a semiconductor switch 30 (switching element) that controls power supply from the capacitor 10 to the solid-state light-emitting elements 20. The solid state light emitting element 20 is placed on the outer surface of the capacitor 10, the semiconductor switch 30 is placed on the outer surface of the capacitor 10 or is provided inside the capacitor 10, and the capacitor 10 has a conductive portion for connecting the solid state light emitting element 20 and the semiconductor switch 30 in series between the external electrode 11 and the external electrode 12. Therefore, the light-emitting device 100 can reduce the parasitic inductance of the current path a by shortening the distance between the currents that face each other and flow in opposite directions to the distance h, and can make the light output from the solid state light-emitting element 20 into a short pulse. In addition, in the light-emitting device 100 according to embodiment 1, a structure having a connection electrode 32 provided on an outer surface of the capacitor 10 is shown as a conductive portion.

The capacitor 10 has: an outer surface (mounting portion) of the capacitor 10 mounts one or more solid-state light-emitting elements 20 that emit light by supplying power from the capacitor 10, and a semiconductor switch 30 (switching element) that controls power supply from the capacitor 10 to the solid-state light-emitting elements 20; and a connection electrode 32 (conductive portion) provided on an outer surface of the capacitor 10, for connecting the capacitor 10 and the semiconductor switch 30 in series. Therefore, by placing the solid-state light-emitting element 20 and the semiconductor switch 30 on the outer surface of the capacitor 10, the distance between the currents flowing in opposite directions can be reduced to the distance h, and the parasitic inductance of the current loop a can be reduced, so that the light output from the solid-state light-emitting element 20 can be made into a short pulse.

(embodiment 2)

In the light-emitting device 100 according to embodiment 1, as shown in fig. 1 (b), external electrodes 11 and 12 are formed at each end of the laminate, and the size of the current loop a is limited by the external dimensions of the capacitor 10. Therefore, in embodiment 2 of the present invention, the capacitor has a structure in which the external electrode and the internal electrode are electrically connected using a via conductor. Fig. 3 is a schematic diagram for explaining the structure of a light-emitting device 100a according to embodiment 2 of the present invention. Fig. 3 (a) shows a top view of the light emitting device 100a as seen from the outer surface of the capacitor 10a on which the solid state light emitting element 20 is mounted, fig. 3 (b) shows a cross-sectional view on the I-I surface of the light emitting device 100a, and fig. 3 (c) shows a cross-sectional view on the II-II surface of the light emitting device 100 a. In addition, the same reference numerals are given to the same structures as those of the light emitting device 100 shown in fig. 1 in the light emitting device 100a shown in fig. 3, and detailed description is not repeated.

The light-emitting device 100a shown in fig. 3 includes a capacitor 10a, a solid-state light-emitting element 20 mounted on an outer surface of the capacitor 10a, and a semiconductor switch 30a. The capacitor 10a is a power supply capacitor, and is formed of a laminated ceramic capacitor. Therefore, the capacitor 10a is a laminate in which a plurality of internal electrodes 14 and 15 for obtaining capacitance and the dielectric ceramic layer 13 are alternately laminated.

As shown in fig. 3 (b), the capacitor 10a is formed with via conductors 16 and 17 penetrating the laminate. The via conductor 16 electrically connects the external electrode 11 formed on the outer surface of the capacitor 10a with the stacked internal electrode 14. As shown in fig. 3 (c), the internal electrode 14 is electrically connected to the via conductor 16, but is not electrically connected to the via conductor 17. The via conductor 17 electrically connects the external electrode 12 formed on the outer surface of the capacitor 10a and the stacked internal electrode 15. Although not shown, the internal electrode 15 is electrically connected to the via conductor 17, but is not electrically connected to the via conductor 16.

The semiconductor switch 30a forms one electrode (e.g., drain electrode) and the other electrode (e.g., source electrode) on the same surface. Accordingly, the semiconductor switch 30a connects one electrode (e.g., drain electrode) with the connection electrode 32, and electrically connects the other electrode (e.g., source electrode) with the external electrode 12.

The outer electrode 11 and the inner electrode 14 are connected by the via conductor 16 penetrating the laminate, and the outer electrode 12 and the inner electrode 15 are connected by the via conductor 17 penetrating the laminate, whereby the distance between the via conductor 16 and the via conductor 17 is shorter than the distance between the outer electrode 11 and the outer electrode 12 formed on the end face of the capacitor 10 as shown in fig. 1 (b). Therefore, the current loop of the light emitting device 100a is smaller than the current loop a of the light emitting device 100, and parasitic inductance of the light emitting device 100a can be further reduced.

The via conductors 16 and 17 are formed inside the capacitor 10a, but are preferably formed below the position where the solid state light emitting element 20 and the semiconductor switch 30a are mounted. Specifically, the via conductor 16 is provided near one electrode (for example, anode) of the solid-state light-emitting element 20, and the via conductor 17 is provided near the other electrode (for example, source electrode) of the semiconductor switch 30 a. This shortens the connection distance from the solid-state light-emitting element 20 to the capacitor 10a, shortens the connection distance from the semiconductor switch 30a to the capacitor 10a, and further reduces the current loop of the light-emitting device 100 a.

As described above, the capacitor 10a of the light emitting device 100a according to embodiment 2 includes the via conductor 16 (first via conductor) electrically connected to the internal electrode 14 and the solid state light emitting element 20, and the via conductor 17 (second via conductor) electrically connected to the internal electrode 15 and the semiconductor switch 30 a. Further, the via conductors 16, 17 are electrically connected to the external electrodes 11, 12 of the capacitor 10 a.

Therefore, the light emitting device 100a can connect the solid state light emitting element 20, the semiconductor switch 30a, and the internal electrodes 14 and 15 of the capacitor 10a on the inner side than the outer dimension of the capacitor 10a by forming the via conductors 16 and 17, thereby further reducing the current loop and further reducing the parasitic inductance. Although the structure in which the via conductors are formed in the capacitor 10a as the multilayer ceramic capacitor has been described above, the structure in which the via conductors are formed may be employed for other types of capacitors (semiconductor capacitors as an example) described below.

The via conductor 16 (first via conductor) may be provided at a position connected to one end (for example, anode) of the solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10a, and the via conductor 17 (second via conductor) may be provided at a position connected to one end (for example, source electrode) of the semiconductor switch 30a mounted on the outer surface of the capacitor 10 a. Thus, the light emitting device 100a can further reduce the current loop and parasitic inductance by shortening the connection distance between the solid state light emitting element 20 and the semiconductor switch 30a and the capacitor 10 a.

Embodiment 3

In the light-emitting device 100 according to embodiment 1, a structure including the capacitor 10, the solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10, and the semiconductor switch 30 is described. However, the element mounted on the outer surface of the capacitor is not limited to the solid-state light-emitting element and the semiconductor switch. Therefore, in embodiment 3 of the present invention, a structure in which elements other than the solid state light emitting element and the semiconductor switch are mounted on the outer surface of the capacitor will be described.

Fig. 4 is a schematic diagram for explaining the structure of a light-emitting device 100b according to embodiment 3 of the present invention. Fig. 4 (a) shows a top view of the light emitting device 100b as seen from the outer surface of the capacitor 10a on which the solid state light emitting element 20 is mounted, fig. 4 (b) shows a cross-sectional view on the I-I surface of the light emitting device 100b, and fig. 4 (c) shows a cross-sectional view on the II-II surface of the light emitting device 100 b. In addition, the same components of the light emitting device 100b shown in fig. 4 as those of the light emitting device 100 shown in fig. 1 and the light emitting device 100a shown in fig. 2 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100b shown in fig. 4 includes a capacitor 10a, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10a, a semiconductor switch 30a, and a clamp diode 40. The capacitor 10a is a power supply capacitor, and is formed of a laminated ceramic capacitor. Therefore, the capacitor 10a is a laminate in which a plurality of internal electrodes 14 and 15 for obtaining capacitance and the dielectric ceramic layer 13 are alternately laminated.

As shown in fig. 4 (b) and 4 (c), the capacitor 10a is formed with via conductors 16 and 17 penetrating the laminate. The via conductor 16 electrically connects the external electrode 11 formed on the outer surface of the capacitor 10a with the stacked internal electrode 14. The via conductor 17 electrically connects the external electrode 12 formed on the outer surface of the capacitor 10a and the stacked internal electrode 15.

The solid state light emitting element 20 connects one electrode (e.g., cathode) with the external electrode 11, and the other electrode (e.g., anode) with the wiring 21. The wiring 21 electrically connects the solid state light emitting element 20 and the connection electrode 32. As a material of the wiring 21, au, al, cu, or the like can be used. The wiring 21 may be in the shape of an electric wire, a band, a clip, or the like.

One electrode (for example, anode) of the clamp diode 40 is electrically connected to the external electrode 11 in addition to the solid-state light-emitting element 20. The clamp diode 40 is connected in parallel with the solid-state light emitting element 20, and the other electrode (e.g., cathode) is electrically connected to the wiring 41. The wiring 41 electrically connects the clamp diode 40 to the connection electrode 32. As a material of the wiring 41, au, al, cu, or the like can be used.

One electrode (e.g., a source electrode) and the other electrode (e.g., a drain electrode) of the semiconductor switch 30a are formed on the same surface. Accordingly, the semiconductor switch 30a connects one electrode (e.g., a source electrode) with the connection electrode 32, and electrically connects the other electrode (e.g., a drain electrode) with the external electrode 12.

Fig. 5 is a circuit diagram of a light-emitting device 100b according to embodiment 3 of the present invention. In the circuit diagram shown in fig. 5, one electrode (cathode) of the solid-state light-emitting element 20 and one electrode (anode) of the clamp diode 40 are connected to one electrode of the capacitor 10 a. The other electrode of the capacitor 10a is connected to one electrode (drain electrode) of the semiconductor switch 30 a. The other electrode (anode) of the solid-state light-emitting element 20, the other electrode (cathode) of the clamp diode 40, and the other electrode (source electrode) of the semiconductor switch 30a are connected to the GND wiring.

The semiconductor switch 30a used in the light emitting device 100b is shared with the semiconductor switch used in the booster circuit 200. Therefore, the booster circuit 200 includes the semiconductor switch 30a of the light-emitting device 100b in addition to the dc power supply 201, the inductor 202, and the diode 203. In other words, the light-emitting device 100b is configured such that a semiconductor switch used in the booster circuit 200 is also placed on the outer surface of the capacitor 10 a.

As described above, in the light emitting device 100b according to embodiment 3, the clamp diode 40 is connected in parallel with the solid state light emitting element 20 and is placed on the outer surface of the capacitor 10a, so that the parasitic inductance can be reduced by reducing the current loop, and the light output from the solid state light emitting element 20 can be made into a short pulse. The light-emitting device 100b using the capacitor 10a as the multilayer ceramic capacitor has been described above, but the same structure may be used for other types of capacitors (semiconductor capacitors as an example) described below.

Embodiment 4

In the light-emitting device 100b according to embodiment 3, as shown in fig. 4 (a), since the clamp diode 40 is present in the light-emitting portion 22 of the solid-state light-emitting element 20 on the clamp diode 40 side on the optical path, there is a possibility that the emitted light is blocked by the clamp diode 40. Therefore, in embodiment 4 of the present invention, the arrangement of the elements that do not block the optical path of the light emitted from the light emitting section 22 of the solid state light emitting element 20 will be described.

Fig. 6 is a schematic diagram for explaining the structure of a light-emitting device 100c according to embodiment 4 of the present invention. The plan view shown in fig. 6 is a plan view of the light emitting device 100c viewed from the outer surface of the capacitor 10a on which the solid state light emitting element 20 is mounted. In addition, the same components in the light-emitting device 100c shown in fig. 6 as those in the light-emitting device 100b shown in fig. 4 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The solid state light emitting element 20 is an edge light emitting type light emitting element having a light emitting portion 22 that emits light in a direction parallel to the outer surface of the capacitor 10 a. Therefore, the light emitting device 100c can output light in a direction parallel to the outer surface of the capacitor 10 a. However, it is necessary to configure such that the light emitted from the light emitting section 22 is not blocked by other elements (e.g., semiconductor switches, clamp diodes, etc.).

The light-emitting device 100c shown in fig. 6 includes a capacitor 10a, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10a, a semiconductor switch 30a, and a clamp diode 40. Further, the light emitting device 100c is arranged so that the position of the clamp diode 40 is shifted to the right side of the paper surface as compared with the light emitting device 100b shown in fig. 4. Therefore, no other element is present at a position where the optical path L of the light emitted from the light emitting portion 22 is blocked.

In particular, in the case where the light emitting device has a structure in which no light emission is detected by a light receiving element such as a photodiode, it is necessary to secure a place where the light receiving element is placed on the optical path L of light. In the light emitting device 100c shown in fig. 6, since the clamp diode 40 and the semiconductor switch 30a are arranged to be shifted to the right side of the drawing, for example, the light receiving element 50 can be placed on the external electrode 11 at a position of the light path L that blocks light. In the light-emitting device, even if the light-receiving element detects no light emission, if another element is present at a position where the optical path L is blocked, the emitted light is reflected by the other element and returns to the solid-state light-emitting element 20, and it is considered that the resonance operation in the solid-state light-emitting element 20 is adversely affected. Therefore, in order to avoid such a negative influence, it is also desirable to configure such that no other element is present on the optical path L.

As a method of disposing the light emitted from the light emitting portion 22 so as not to be blocked by other elements, a method of disposing other elements on the outer surface of the capacitor so as to be shifted in the horizontal direction with respect to the solid state light emitting element 20, as in the light emitting device 100c shown in fig. 6, and also a method of disposing other elements so as to be shifted in the vertical direction, may be considered.

Fig. 7 is a schematic diagram for explaining the structure of another light-emitting device 100d according to embodiment 4 of the present invention. Fig. 7 (a) is a plan view of the light emitting device 100d as seen from the outer surface of the capacitor 10a on which the solid state light emitting element 20 is mounted, and fig. 7 (b) is a cross-sectional view of the light emitting device 100d on the I-I plane. In addition, the same components of the light emitting device 100d shown in fig. 7 as those of the light emitting device 100b shown in fig. 4 and the light emitting device 100c shown in fig. 6 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The solid state light emitting element 20 is an edge light emitting type light emitting element having a light emitting portion 22 that emits light in a direction parallel to the outer surface of the capacitor 10 a. Therefore, the light emitting device 100d can output light in a direction parallel to the outer surface of the capacitor 10 a. However, it is necessary to configure such that the light emitted from the light emitting section 22 is not blocked by other elements (e.g., semiconductor switches, clamp diodes, etc.). Therefore, in the light emitting device 100d, the metal plate 23 is placed on the external electrode 11, and the solid state light emitting element 20 is placed on the metal plate 23. In other words, the mounting surface of the solid state light emitting element 20 is lifted in the vertical direction with respect to the mounting surfaces of the other elements. Therefore, as shown in fig. 7 (b), no other element is present at a position where the optical path L of the light emitted from the light emitting section 22 is blocked.

The metal plate 23 may be a bonding member capable of electrically connecting the external electrode 11 and one electrode (for example, a cathode) of the solid-state light-emitting element 20. The thickness of the metal plate 23 may be sufficiently high so that the other elements do not block the optical path L of the light emitted from the solid state light emitting element 20.

As described above, the solid state light emitting element 20 of the light emitting devices 100c and 100d according to embodiment 4 can emit light in the horizontal direction with respect to the outer surface of the capacitor 10a, and can emit light without being blocked by other members mounted on the capacitor 10 a. In other words, the other member placed on the outer surface of the capacitor 10a is placed on the outer surface of the capacitor so as to avoid the optical path L of the light emitted from the solid state light emitting element 20. As other components mounted on the outer surface of the capacitor 10a, for example, a semiconductor switch 30a, a clamp diode 40, and the like are provided.

For example, as shown in fig. 6, the semiconductor switch 30a is disposed on the outer surface of the capacitor 10a so as to be apart in the horizontal direction with respect to the solid-state light-emitting element 20. As shown in fig. 7, the semiconductor switch 30a is disposed on the outer surface of the capacitor 10a so as to be offset in the vertical direction with respect to the solid-state light-emitting element 20. By disposing in this manner, no other element (for example, a semiconductor switch, a clamp diode, or the like) is disposed on the optical path L of the solid-state light-emitting element 20, and thus a light-receiving element such as a photodiode can be disposed.

The light emitting devices 100c and 100d may further include a light receiving element 50 for receiving light from the solid state light emitting element 20 on the optical path L of the light emitted from the solid state light emitting element 20. When other elements are present on the optical path L of the solid-state light-emitting element 20, it is necessary to dispose the light-receiving element 50 in front of the other elements or to reflect light and detect the light by the light-receiving element 50. If the light receiving element 50 is arranged in front of the other element, a detour connection wiring is required, and the parasitic inductance of the current loop increases. In addition, in order to reflect light and detect the light by the light receiving element 50, a new mirror or other member needs to be provided, and the cost of the light emitting device increases and the size increases. The light receiving element 50 may not be placed on the outer surface of the capacitor 10 a. The light emitting devices 100c and 100d using the capacitor 10a of the multilayer ceramic capacitor have been described above, but the same structure may be used for other types of capacitors (semiconductor capacitors as an example) described below.

Embodiment 5

In the light-emitting device 100 according to embodiment 1, as shown in fig. 1 (b), the capacitor 10 is constituted by a laminated ceramic capacitor. Therefore, in embodiment 5 of the present invention, a case will be described in which a capacitor is of a type other than a laminated ceramic capacitor. Hereinafter, a case of using a semiconductor capacitor will be described as an example, but the type of the capacitor is not limited thereto.

Fig. 8 is a schematic diagram for explaining the structure of a light-emitting device 100e according to embodiment 5 of the present invention. Fig. 8 (a) is a plan view of the light emitting device 100e as seen from the outer surface of the capacitor 10b on which the solid state light emitting element 20 is mounted, and fig. 8 (b) is a cross-sectional view of the light emitting device 100e on the I-I plane. In addition, the same components of the light emitting device 100e shown in fig. 8 as those of the light emitting device 100 shown in fig. 1 and the light emitting device 100a shown in fig. 3 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100e shown in fig. 8 includes a capacitor 10b, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10b, and a semiconductor switch 30a. The capacitor 10b is a power supply capacitor, and is formed of a semiconductor capacitor. The capacitor 10b is formed by a semiconductor process, and is composed of an n+ layer 15a formed by implanting N-type impurity ions into a silicon substrate 18, a dielectric layer 13a formed on the surface thereof by, for example, a CVD (Chemical Vapor Deposition: chemical vapor deposition) method or the like and made of, for example, an inorganic material such as silicon oxide, silicon nitride, hafnium oxide, hafnium silicate, aluminum oxide, barium titanate or the like, and a polysilicon layer 14a of an electric conductor formed on the surface of the dielectric layer 13a by a CVD method. The substrate on which the capacitor 10b is formed is described as the silicon substrate 18, but may be a substrate such as a sapphire substrate or a GaAs substrate.

The n+ layer 15a is a low-resistance layer formed by forming a plurality of grooves or a plurality of pillars on the silicon substrate 18 to form a convex-concave shape, and implanting N-type impurity ions into the surface of the formed convex-concave shape at a high concentration. This is to enlarge the area of the dielectric layer 13a sandwiched by the n+ layer 15a and the polysilicon layer 14a to increase the capacitance of the capacitor. Accordingly, the number and size of the trenches or pillars formed in the silicon substrate 18 are designed according to the capacitance required for the capacitor 10 b. The structure of the capacitor 10b is an example, and is not limited to the above-described structure. The dielectric layer 13a is described as one layer in fig. 8 (b), but may be formed of the same material or different materials. Further, in the capacitor 10b, the n+ layer 15a is formed by implanting N-type impurity ions into the silicon substrate 18, but the p+ layer may be formed by implanting P-type impurity ions into the silicon substrate 18 according to the circuit configuration and manufacturing.

The polysilicon layer 14a is used as one electrode (first internal electrode) forming the capacitance of the capacitor 10 b. By forming the metal layer 14b on the upper layer of the polysilicon layer 14a, the resistivity of one electrode formed of the polysilicon layer 14a is reduced. Further, the metal layer 14b may not be formed if the desired resistivity can be obtained only by the polysilicon layer 14 a. The polysilicon layer 14a having the metal layer 14b formed thereon is electrically connected to the external electrode 11a via the via conductor 16 a. The polysilicon layer 14a forms one electrode (first internal electrode) that forms the capacitance of the capacitor 10b, but the electrode may be formed of a metal layer or the like.

The n+ layer 15a is used as the other electrode (second internal electrode) forming the capacitance of the capacitor 10 b. The n+ layer 15a is electrically connected to the external electrode 12a via the via conductor 17 a.

The external electrodes 11a and 12a are electrodes on the outer surface of the capacitor 10b, on which the solid-state light-emitting element 20 and the semiconductor switch 30a are mounted. Specifically, in the capacitor 10b shown in fig. 8, the external electrode 11a is formed on the left side of the outer surface on the paper surface, and the external electrode 12a is formed on the right side of the outer surface on the paper surface. Further, a gate extraction electrode 31 and a connection electrode 32 are formed between the external electrodes 11a and 12a on the outer surface of the capacitor 10 b.

The solid state light emitting element 20 connects one electrode (for example, anode) with the external electrode 11a, and the other electrode (for example, cathode) with the wiring 21. The wiring 21 electrically connects the solid state light emitting element 20 and the connection electrode 32.

The semiconductor switch 30a connects one electrode (e.g., drain electrode) with the connection electrode 32, and electrically connects the other electrode (e.g., source electrode) with the external electrode 12a. The circuit configuration of the light emitting device 100e is the circuit configuration shown in fig. 2, but the configuration of the semiconductor capacitor described above may be applied to the circuit configuration shown in fig. 5.

In the light emitting device 100e, for example, after forming the insulating film 19 having a thickness of 100 μm or less such as silicon oxide or silicon nitride on the metal layer 14b, the external electrodes 11a and 12a, the connection electrode 32, and the via conductors 16a and 17a are formed by a semiconductor process. Therefore, in the light-emitting device 100e, the distance between the capacitor 10b and the external electrodes 11a and 12a can be further shortened by the fine processing, and the current loop can be further reduced as compared with the case where the solid state light-emitting element 20 and the semiconductor switch 30a are mounted on the outer surface of the laminated ceramic capacitor. Although not shown, a passivation layer is formed as a protective film on the outer surface of the capacitor 10b except for the position where the solid-state light-emitting element 20 is connected to the external electrode 11a, the position where the semiconductor switch 30a is connected to the external electrode 12a, and the position where the connection electrode 32 is connected to the wiring 21. Although the insulating film 19 described in fig. 8 (b) is described as using an inorganic material such as silicon oxide or silicon nitride, it may be formed in combination with an insulating film using an organic material such as polyimide or resin shown in fig. 16 (b) so that the insulating film and the wiring layer are not formed in the preceding step of the semiconductor as will be described later, but are formed by a re-wiring step. Further, since the parasitic capacitance is generated between the metal layer 14b and the connection electrode 32 by providing the insulating film 19, the material of the insulating film 19 is selected so that the dielectric constant of the insulating film 19 is lower than that of the dielectric layer 13a, and thus the influence of the parasitic capacitance on the driving of the solid state light emitting element 20 can be suppressed.

As described above, the capacitor 10b of the light emitting device 100e according to embodiment 5 is a semiconductor capacitor including the dielectric layer 13a, the polysilicon layer 14a (first internal electrode) and the n+ layer 15a (second internal electrode) disposed through the dielectric layer 13a on the silicon substrate 18 (semiconductor substrate). The semiconductor capacitor has an insulating film 19 of 100 μm or less on the outer surface, and has a connection electrode 32 (conductive portion) provided on the outer surface of the capacitor 10b through the insulating film 19. Therefore, the light-emitting device 100e can reduce the current loop and can further reduce the parasitic inductance of the current loop, and can make the light output from the solid state light-emitting element 20 into a shorter pulse, compared to the case where the element is mounted on the outer surface of the laminated ceramic capacitor.

The dielectric layer 13a of the semiconductor capacitor is formed in a direction perpendicular to the outer surface of the capacitor 10b on which the solid state light emitting element 20 and the semiconductor switch 30a are mounted. In other words, the semiconductor capacitor has a structure in which a plurality of trenches or a plurality of pillars are formed in the silicon substrate 18, N-type impurity ions are implanted into the plurality of trenches or pillars to form a low-resistance layer, and a dielectric layer 13a is formed on the surface thereof and sandwiched between a polysilicon layer 14a (first internal electrode) and an n+ layer 15a (second internal electrode). As described above, the capacitor 10b as a semiconductor capacitor is provided with the convex-concave portion as shown in fig. 8 (b), thereby securing the capacitance value of the capacitor 10 b.

Embodiment 6

In the light-emitting device 100e according to embodiment 5, as shown in fig. 8 (b), the capacitor 10b is formed of a semiconductor capacitor. In the capacitor 10b, the portion forming the convex-concave shape of the capacitance is provided on the entire surface including the rear surface of the solid state light emitting element 20 and the semiconductor switch 30 a. In embodiment 6 of the present invention, a structure in which a metal layer, a polysilicon layer, a silicon substrate, and the like are disposed at positions on the back surfaces of the solid-state light-emitting element 20 and the semiconductor switch 30a without providing a portion of the capacitor where the convex-concave shape of the capacitance is formed will be described. Hereinafter, a case of using a semiconductor capacitor will be described as an example, but the type of the capacitor is not limited thereto.

Fig. 9 is a schematic diagram for explaining the structure of a light-emitting device 100f according to embodiment 6 of the present invention. Fig. 9 (a) is a plan view of the light emitting device 100f as seen from the outer surface of the capacitor 10c on which the solid state light emitting element 20 is mounted, and fig. 9 (b) is a cross-sectional view of the light emitting device 100f on the I-I plane. In addition, the same components of the light emitting device 100f shown in fig. 9 as those of the light emitting device 100 shown in fig. 1, the light emitting device 100a shown in fig. 3, and the light emitting device 100e shown in fig. 8 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100f shown in fig. 9 includes a capacitor 10c, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10c, and a semiconductor switch 30a. The capacitor 10c is a power supply capacitor, and is formed of a semiconductor capacitor. The capacitor 10c has the same structure as the capacitor 10b shown in fig. 8, but as shown in fig. 9 (b), only the metal layer 14b, the polysilicon layer 14a, and the silicon substrate 18 are arranged at different points from each other, without providing a convex-concave portion of the capacitor, at a position where the rear surface of the solid state light emitting element 20 and the semiconductor switch 30a is formed.

The thermal conductivity of the dielectric layer 13a is lower than that of the metal layer 14b, the polysilicon layer 14a (first internal electrode), and the silicon substrate 18. In the capacitor 10b shown in fig. 8, since the dielectric layer 13a is necessarily provided at a portion where the convex-concave shape of the capacitance is formed, it is difficult to release heat from the solid state light emitting element 20 and the semiconductor switch 30a as heat generating sources.

Therefore, in the light-emitting device 100f, the portion of the capacitor 10c forming the convex-concave shape of the capacitance is not provided at the position of the rear surface of the solid-state light-emitting element 20 or the semiconductor switch 30a, and the dielectric, the insulating film, and the air are not disposed. Instead, the capacitor 10c has a convex portion of the silicon substrate 18 located on the side of the capacitor formation portion formed by the dielectric layer 13a and the polysilicon layer 14a (first internal electrode) and the p+ layer 15b (second internal electrode) provided with the dielectric layer 13a interposed therebetween, immediately below the position where the solid state light emitting element 20 and the semiconductor switch 30a are mounted. Here, the relationship of thermal conductivity is a relationship of metal > silicon/polysilicon > dielectric > insulating film > air. Further, even if the width of the via conductor 17 connected to the p+ layer 15b and the external electrode 12a is increased, the heat dissipation performance is improved. In order to ensure insulation between the silicon substrate 18 and the second internal electrode of the capacitor 10c, it is necessary to reverse the polarity of the silicon substrate 18 to the polarity of the second internal electrode. In order to prevent a current from flowing through the parasitic diode generated at this time, a circuit configuration to give a reverse bias is necessary. In embodiment 6, according to the above-described circuit configuration, the second internal electrode of the capacitor 10c is made to be the p+ layer 15b, so that the parasitic diode is reverse-biased.

As described above, the semiconductor capacitor of the capacitor 10c of the light-emitting device 100f according to embodiment 6 has the convex portion of the silicon substrate 18 (semiconductor substrate) located on the side of the capacitance forming portion formed by the dielectric layer 13a and the polysilicon layer 14a (first internal electrode) and the p+ layer 15b (second internal electrode) provided with the dielectric layer 13a interposed therebetween, immediately below the position where the solid-state light-emitting element 20 and the semiconductor switch 30a are mounted. Therefore, the light-emitting device 100f is configured such that the convex portion of the silicon substrate 18 having the higher thermal conductivity than the dielectric layer 13a is disposed without providing the convex-concave-shaped portion including the dielectric layer 13a having the lower thermal conductivity than the polysilicon layer 14a, and thus, heat is easily released to the rear surface of the silicon substrate 18 as compared with the case where the dielectric layer 13a is provided on the rear surfaces of the solid-state light-emitting element 20 and the semiconductor switch 30 a.

(modification)

Since the thermal conductivity of the polysilicon layer 14a is higher than that of the dielectric layer 13a, the dielectric layer 13a may not be provided at a portion where the capacitance of the capacitor is formed immediately below the position where the solid state light emitting element 20 and the semiconductor switch 30a are mounted, and only the convex-concave portion of the polysilicon layer 14a may be provided at the silicon substrate 18.

Fig. 10 is a schematic diagram for explaining a structure of a light-emitting device 100g according to a modification of embodiment 6 of the present invention. Fig. 10 (a) shows a top view of the light emitting device 100g as seen from the outer surface of the capacitor 10d on which the solid state light emitting element 20 is mounted, and fig. 10 (b) shows a cross-sectional view on the I-I plane of the light emitting device 100 g. In addition, the same components of the light emitting device 100g shown in fig. 10 as those of the light emitting device 100 shown in fig. 1, the light emitting device 100a shown in fig. 3, and the light emitting device 100e shown in fig. 8 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100g shown in fig. 10 includes a capacitor 10d, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10d, and a semiconductor switch 30a. The capacitor 10d is a power supply capacitor, and is formed of a semiconductor capacitor. The capacitor 10d has the same structure as the capacitor 10b shown in fig. 8, but as shown in fig. 10 (b), the capacitor is different from the capacitor in that the capacitor has a convex-concave shape portion where the dielectric layer 13a is not provided and only the polysilicon layer 14a is provided at a position to be the rear surface of the solid state light emitting element 20 or the semiconductor switch 30a. In other words, the solid-state light-emitting element 20 and the semiconductor switch 30a have portions where only the polysilicon layer 14a and the silicon substrate 18 are provided.

As described above, the semiconductor capacitor of the capacitor 10d of the light-emitting device 100g according to the modification example of embodiment 6 has a portion where the dielectric layer 13a is not provided immediately below the position where the solid-state light-emitting element 20 and the semiconductor switch 30a are mounted, but only the polysilicon layer 14a, the metal layer 14b, and the silicon substrate 18 are provided. Therefore, the light-emitting device 100g has a portion having a convex-concave shape where the dielectric layer 13a having a lower thermal conductivity than the polysilicon layer 14a is not provided, and thus, compared with the case where the dielectric layer 13a is provided on the rear surface of the solid state light-emitting element 20 and the semiconductor switch 30a, heat is easily released to the rear surface of the silicon substrate 18.

Embodiment 7

As shown in fig. 9 (b), in the light-emitting device 100f according to embodiment 6, a convex portion of the silicon substrate 18 is arranged at a position on the back surface of the solid-state light-emitting element 20 or the semiconductor switch 30a, without providing a convex-concave-shaped portion that forms the capacitance of the capacitor 10 c. In embodiment 7 of the present invention, a structure in which a via conductor is further provided at a position to be a rear surface of the solid-state light-emitting element 20 or the semiconductor switch 30a will be described. Hereinafter, a case of using a semiconductor capacitor will be described as an example, but the type of the capacitor is not limited thereto.

Fig. 11 is a schematic diagram for explaining the structure of a light-emitting device 100h according to embodiment 7 of the present invention. Fig. 11 (a) shows a top view of the light emitting device 100h as seen from the outer surface of the capacitor 10e on which the solid state light emitting element 20 is mounted, and fig. 11 (b) shows a cross-sectional view on the I-I plane of the light emitting device 100 h. In addition, the same components of the light emitting device 100h shown in fig. 11 as those of the light emitting device 100 shown in fig. 1, the light emitting device 100a shown in fig. 3, and the light emitting device 100f shown in fig. 9 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100h shown in fig. 11 includes a capacitor 10e, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10e, and a semiconductor switch 30a. The capacitor 10e is a power supply capacitor, and is formed of a semiconductor capacitor. The capacitor 10e has the same structure as the capacitor 10c shown in fig. 9, but as shown in fig. 11 (b), the point where the through hole conductors 16b and 17b are provided at positions on the back surfaces of the solid state light emitting element 20 and the semiconductor switch 30a is different. Further, the via hole conductor 16b is formed with an insulating film 16d around the n+ layer 15a, which is a second internal electrode of the capacitor 10e, and the silicon substrate 18, in order to ensure insulation. In addition, the via hole conductor 17b is formed with an insulating film 17d around in order to ensure insulation from the silicon substrate 18 of the capacitor 10 e. In fig. 11 (b), the insulating films 16d and 17d are formed to insulate the 2 electrodes of the capacitor 10e, but the 2 electrodes of the capacitor can be insulated by forming an n+ layer and a p+ layer around the via conductors 16b and 17b, depending on the circuit configuration, the component arrangement, and the structure of the semiconductor capacitor to be formed.

The light emitting device 100h is provided with via conductors 16b and 17b for further improving heat dissipation. Through hole conductors 16b and 17b are provided from external electrodes 11a and 12a connected to heat sources of the solid state light emitting element 20, the semiconductor switch 30a, and the like toward the back surface of the silicon substrate 18. In other words, the via conductors 16b and 17b are third via conductors connected to the via conductor 16a (first via conductor) electrically connected to the external electrode 11a and the via conductor 17a (second via conductor) electrically connected to the external electrode 12a, respectively.

The via conductors 16b and 17b are formed to a surface (rear surface of the silicon substrate 18) opposite to the outer surface of the semiconductor capacitor on which the solid state light emitting element 20 and the semiconductor switch 30a are mounted, and are made of a material having a higher thermal conductivity than the silicon substrate 18. Therefore, the light emitting device 100h easily releases heat of the solid state light emitting element 20 and the semiconductor switch 30a via the via conductors 16b, 17b, as compared with the case of only the silicon substrate 18. Further, the light emitting device 100h can be connected to the external electrodes 11a and 12a from the back surface side of the silicon substrate 18 by providing the external electrodes 16c and 17c electrically connected to the via conductors 16b and 17b on the back surface of the silicon substrate 18.

As described above, the via conductors 16a and 17a of the light emitting device 100h according to embodiment 7 are electrically connected to the via conductors 16b and 17b reaching the surface (the back surface of the silicon substrate 18) opposite to the outer surface of the semiconductor capacitor on which the solid state light emitting element 20 and the semiconductor switch 30a are mounted, respectively. Therefore, the light-emitting device 100h can conduct heat from the solid-state light-emitting element 20 and the semiconductor switch 30a to the via conductors 16b and 17b, and therefore, heat of the solid-state light-emitting element 20 and the semiconductor switch 30a is easily released.

The via conductors 16b and 17b are preferably made of a material having higher thermal conductivity than silicon.

(other modifications)

(1) In the capacitor 10b according to embodiment 5, a description is given of a semiconductor capacitor having a convex-concave shape. However, the internal electrode of the semiconductor capacitor and the dielectric layer interposed between the internal electrodes may be formed of parallel plates.

Fig. 12 is a schematic diagram for explaining the structure of a light-emitting device according to modification (1) of the present invention. Fig. 12 (a) is a plan view of the light emitting device 100I as seen from the outer surface of the capacitor 10f on which the solid state light emitting element 20 is mounted, and fig. 12 (b) is a cross-sectional view of the light emitting device 100I on the I-I plane. In addition, the same components of the light emitting device 100i shown in fig. 12 as those of the light emitting device 100 shown in fig. 1, the light emitting device 100a shown in fig. 3, and the light emitting device 100e shown in fig. 8 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100i shown in fig. 12 includes a capacitor 10f, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10f, and a semiconductor switch 30a. The capacitor 10f is a power supply capacitor, and is formed of a semiconductor capacitor. The capacitor 10f is formed by a semiconductor process, and is composed of a flat n+ layer 15c formed by implanting N-type impurity ions into a silicon substrate 18 at a high concentration, a flat dielectric layer 13c formed by a CVD method on the surface thereof, and a flat polysilicon layer 14c formed by a CVD method on the surface of the dielectric layer 13 c. In the capacitor 10f, the n+ layer 15a is formed by implanting N-type impurity ions into the silicon substrate 18, but the p+ layer may be formed by implanting P-type impurity ions into the silicon substrate 18 according to the circuit configuration and manufacturing.

The structure of the capacitor 10f is an example, and is not limited to the above-described structure. The n+ layer 15c, the dielectric layer 13c, and the polysilicon layer 14c may be stacked in a plurality of layers instead of 1 layer each.

(2) In the light-emitting device 100 according to embodiment 1, the description has been made as the connection electrode 32 formed on the outer surface of the capacitor 10 and connected to one electrode of the semiconductor switch 30, as the conductive portion for connecting the solid-state light-emitting element 20 and the semiconductor switch 30 in series. However, the present invention is not limited to this, and the connection electrode 32 may not be provided.

Fig. 13 is a schematic diagram for explaining the structure of a light-emitting device according to modification (2) of the present invention. Fig. 13 (a) shows a top view of the light emitting device 100j as seen from the outer surface of the capacitor 10 on which the solid state light emitting element 20 is mounted, and fig. 13 (b) shows a cross-sectional view on the I-I plane of the light emitting device 100 j. In addition, the same components in the light emitting device 100j shown in fig. 13 as those in the light emitting device 100 shown in fig. 1 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100j shown in fig. 13 includes a capacitor 10, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10, and a semiconductor switch 30. The capacitor 10 has external electrodes 11 and 12 formed on the outer surfaces of the solid-state light-emitting element 20 and the semiconductor switch 30. Specifically, in the capacitor 10 shown in fig. 13, the external electrode 11 is formed on the left side of the outer surface on the paper surface, and the external electrode 12 is formed on the right side of the outer surface on the paper surface.

The solid state light emitting element 20 connects one electrode (for example, anode) with the external electrode 11, and the other electrode (for example, cathode) with the wiring 21 a. The semiconductor switch 30 connects one electrode (for example, a drain electrode) to the wiring 21a and the other electrode (for example, a source electrode) to the external electrode 12 using, for example, silicon MOSFET, gaNFET or the like. The gate electrode of the semiconductor switch 30 is electrically connected to a gate extraction electrode 31 formed on the outer surface of the capacitor 10.

The wiring 21a is an inter-element connection electrode composed of 1 metal plate connecting the solid-state light-emitting element 20 and the semiconductor switch 30 in series. Here, the wiring 21a is a conductive portion for connecting the solid-state light-emitting element 20 and the semiconductor switch 30 in series. When the solid-state light-emitting element 20 and the semiconductor switch 30 have the same thickness, the wiring 21a connecting the two is formed in a flat metal plate shape as shown in fig. 13 (b). By connecting the solid-state light-emitting element 20 and the semiconductor switch 30 in series with the wiring 21a, the current loop a1 flowing through the capacitor 10, the solid-state light-emitting element 20, and the semiconductor switch 30 can be reduced in the same manner as the current loop a shown in fig. 1 (b).

The current flowing through the wiring 21a in the current circuit a1 (solid arrow) and the current flowing through the internal electrodes 14 and 15 (broken arrow) are also opposite and facing each other. The direction of the current flowing through the wiring 21a (arrow of solid line) and the direction of the current flowing through the internal electrodes 14 and 15 (arrow of broken line) are opposed to each other by the distance h of the outer thickness of the capacitor 10, the thickness m of the external electrode, and the sum of the thicknesses n of the solid-state light emitting element 20 and the semiconductor switch 30. Here, the thickness of the external electrode is about 10 μm, and the thickness of the solid-state light-emitting element 20 or the semiconductor switch 30 is also 200 μm or less. Therefore, the distance between the current flowing through the wiring 21a (solid arrow) and the direction of the current flowing through the internal electrodes 14 and 15 (broken arrow) is shorter than in the conventional case of connection through wiring, and the parasitic inductance of the current loop a1 can be reduced.

(3) In the modification (2), the shape of the wiring 21a is described as a flat metal plate. However, the shape of the wiring 21a is not limited to this, and may be other than the shape of a flat metal plate.

Fig. 14 is a schematic diagram for explaining a structure of a light-emitting device according to modification (3) of the present invention. Fig. 14 (a) shows a cross-sectional view of the light-emitting device 100k on the I-I plane, and fig. 14 (b) shows a cross-sectional view of the light-emitting device 100l on the I-I plane. The plan view of the light emitting device 100k and the plan view of the light emitting device 100l are the same as the plan view of the light emitting device 100j shown in fig. 13 (a). Note that, the same reference numerals are given to the same components as those of the light emitting devices 100 shown in fig. 1 and the light emitting device 100j shown in fig. 13 among the light emitting devices 100k and 100l shown in fig. 14, and detailed description thereof will not be repeated.

The wiring 21b shown in fig. 14 (a) is an inter-element connection electrode composed of 1 metal plate connecting the solid-state light-emitting element 20 and the semiconductor switch 30 in series. When the thickness of the semiconductor switch 30 is larger than the thickness of the solid-state light-emitting element 20, the cross-sectional shape of the wiring 21b connecting the two is a key shape or a step shape as shown in fig. 14 (a). By connecting the solid-state light-emitting element 20 and the semiconductor switch 30 in series by the wiring 21b, the current loop a2 flowing through the capacitor 10, the solid-state light-emitting element 20, and the semiconductor switch 30 can be reduced in the same manner as the current loop a shown in fig. 1 (b).

In the wiring 21b, the portion connected to the solid-state light-emitting element 20 and in the horizontal direction with respect to the outer surface of the capacitor 10 and the portion connected to the semiconductor switch 30 and in the horizontal direction with respect to the outer surface of the capacitor 10 do not have to be perpendicular to the outer surface of the capacitor 10.

The wiring 21c shown in fig. 14 (b) is an inter-element connection electrode composed of 1 metal plate connecting the solid-state light-emitting element 20 and the semiconductor switch 30 in series. Even in the case where the solid-state light-emitting element 20 and the semiconductor switch 30 have the same thickness, as shown in fig. 14 (b), the shape of the wiring 21c connecting the two is not a flat metal plate, but a T-shaped cross section. By connecting the solid-state light-emitting element 20 and the semiconductor switch 30 in series with the wiring 21c, the current loop a3 flowing through the capacitor 10, the solid-state light-emitting element 20, and the semiconductor switch 30 can be reduced as compared with the current loop a in the case where the connection electrode 32 is provided as shown in fig. 1 (b).

The cross-sectional shape of the wiring 21c is not limited to the T-shape, and may be a shape filling a space between the solid-state light-emitting element 20 and the semiconductor switch 30 as shown in fig. 14 (b). In the wiring 21c, the current flowing between the solid-state light-emitting element 20 and the semiconductor switch 30 can approach the current flowing through the internal electrodes 14 and 15 as compared with the current flowing at the corresponding positions in fig. 13 (b) and 14 (a). Therefore, the parasitic inductance of the current loop a3 can be made smaller than the parasitic inductances of the current loops a1 and a 2.

(4) In the light-emitting device 100e according to embodiment 5, the solid-state light-emitting element 20 and the semiconductor switch 30a are mounted on the outer surface of the capacitor 10 b. However, the present invention is not limited to this, and when a semiconductor capacitor is used as the capacitor, the semiconductor switch 30a may be integrated with the semiconductor capacitor.

Fig. 15 is a schematic diagram for explaining a structure of a light-emitting device according to modification (4) of the present invention. Fig. 15 (a) shows a top view of the light emitting device 100m as seen from the outer surface of the capacitor 10g on which the solid state light emitting element 20 is mounted, fig. 15 (b) shows a cross-sectional view on the I-I surface of the light emitting device 100m, and fig. 15 (c) shows a cross-sectional view on the II-II surface of the light emitting device 100 m. In addition, the same components of the light emitting device 100m shown in fig. 15 as those of the light emitting device 100 shown in fig. 1, the light emitting device 100a shown in fig. 3, and the light emitting device 100e shown in fig. 8 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100m shown in fig. 15 includes a capacitor 10g and a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10 g. As shown in fig. 15 (c), the capacitor 10g has a structure in which a plurality of grooves or a plurality of pillars are formed in the silicon substrate 18 to have a convex-concave shape, P-type impurity ions are implanted into the convex-concave shape to form a p+ layer 15b of a low resistance layer, and a dielectric layer 13a is further formed and sandwiched by polysilicon layers 14 a.

Further, as shown in fig. 15 (b), not only the capacitor 10g but also a semiconductor switch 30b is formed on the silicon substrate 18. The semiconductor switch 30b includes a p+ layer 15c formed by implanting P-type impurity ions into the silicon substrate 18 at a high concentration, an n+ layer 15d formed by implanting N-type impurity ions into the p+ layer 15c at a high concentration, and an n+ layer 15e formed as a source electrode. Further, the semiconductor switch 30b forms a gate oxide film 15f between the n+ layer 15d and the n+ layer 15e, and forms a metal film 31b, a via conductor 31a, and a gate extraction electrode 31 on the gate oxide film 15 f. In the capacitor 10g, the p+ layer 15b and the p+ layer 15c are formed on the silicon substrate 18, and the n+ layer 15d serving as the drain electrode and the n+ layer 15e serving as the source electrode are formed on the p+ layer 15c, but the p+ layer and the n+ layer to be formed may be changed depending on the circuit configuration and the manufacturing.

In other words, the semiconductor switch 30b is not an element mounted on the capacitor 10g, but is provided inside the silicon substrate 18 on which the capacitor 10g of the semiconductor capacitor is formed. As shown in fig. 8, when the semiconductor switch 30a is placed on the outer surface of the capacitor b, the current flowing through the semiconductor switch 30a does not flow through the outer surface of the silicon substrate 18. However, if the semiconductor switch 30b shown in fig. 15 (b) is integrated with the silicon substrate 18, the current flowing through the semiconductor switch 30b flows through the silicon substrate 18, so that the current loop flowing through the capacitor 10g, the solid-state light-emitting element 20, and the semiconductor switch 30b can be reduced, and parasitic inductance of the current loop can be reduced.

Further, as shown in fig. 15 (a), the light-emitting device 100m does not need to mount a component such as a semiconductor switch on the outer surface of the capacitor 10g, but for example, since GND voltage needs to be obtained from the outside as in the circuit diagram shown in fig. 2, an opening is provided in a part of the passivation layer 60 where the external electrode 12a is provided.

(5) In the light-emitting device 100e according to embodiment 5, a description has been given of a case where wiring for mounting the solid-state light-emitting element 20 and the semiconductor switch 30 is formed on the insulating film 19 made of an inorganic material such as silicon oxide or silicon nitride on the outer surface of the capacitor 10 b. However, the wiring for mounting the solid-state light-emitting element 20 and the semiconductor switch 30 may be formed by a rewiring process.

Fig. 16 is a schematic diagram for explaining a structure of a light-emitting device according to modification (5) of the present invention. Fig. 16 (a) is a plan view of the light emitting device 100n as seen from the outer surface of the capacitor 10h on which the solid state light emitting element 20 is mounted, and fig. 16 (b) is a cross-sectional view of the light emitting device 100n on the I-I plane. In addition, the same components of the light emitting device 100n shown in fig. 16 as those of the light emitting device 100 shown in fig. 1, the light emitting device 100a shown in fig. 3, and the light emitting device 100e shown in fig. 8 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100n shown in fig. 16 includes a capacitor 10h, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10h, and a semiconductor switch 30a. The capacitor 10h is formed by forming an insulating film 19 made of an inorganic material such as silicon oxide or silicon nitride on the outer surface, and forming an insulating film 60a made of an organic material such as polyimide or resin on the insulating film 19. Therefore, in the capacitor 10h, instead of forming a wiring layer or the like for mounting the solid-state light-emitting element 20 and the semiconductor switch 30a in the previous step of the semiconductor, a wiring layer or the like can be formed on the insulating film 60a by the rewiring step.

(6) In the light-emitting device according to the above embodiment, the solid-state light-emitting element 20, the semiconductor switches 30 and 30a, and the clamp diode 40 are described as the elements mounted on the outer surface of the capacitor, but the present invention is not limited thereto, and any element may be used as long as it is an element mounted on the capacitor.

(7) In the light-emitting device according to the above embodiment, the solid-state light-emitting element 20 and the semiconductor switches 30 and 30a are mounted on the outer surface of the same capacitor, but the present invention is not limited thereto, and the surface on which the solid-state light-emitting element 20 is mounted may be different from the surface on which the semiconductor switches 30 and 30a are mounted.

(8) In the light-emitting device according to the above embodiment, the solid-state light-emitting element 20 is mounted on the outer surface of one capacitor, but the present invention is not limited to this, and a plurality of solid-state light-emitting elements may be mounted on the outer surface of the capacitor.

(9) In the light-emitting device according to the above embodiment, the description has been made as the solid state light-emitting element 20 having the light-emitting portion 22 that emits light in the direction parallel to the outer surface of the capacitor, but the present invention is not limited to this, and the solid state light-emitting element may have the light-emitting portion 22 that emits light in the direction perpendicular to the outer surface of the capacitor.

(10) In the light-emitting device according to the above embodiment, a structure in which the solid state light-emitting element is mounted on the outer surface of the capacitor and the semiconductor switch is provided on the outer surface or inside the capacitor has been described. In these light emitting devices, a driving element (gate driving element) for driving a semiconductor switch is generally required. In a modification (10) of the present invention, a structure in which a driving element for driving a semiconductor switch is mounted on the outer surface of a capacitor in addition to the solid-state light-emitting element and the semiconductor switch is described.

Fig. 17 is a circuit diagram of a light-emitting device 100p including a driving element 300 for driving a semiconductor switch 30 a. In the light-emitting device 100p of fig. 17, a driving element 300 and a capacitor 10i-2 for supplying power to the driving element 300 are added to the structure of the light-emitting device 100 shown in fig. 2. In the light emitting device 100p of fig. 17, the same reference numerals are given to the same structures as those of the light emitting device 100 shown in fig. 2, and detailed description is not repeated.

In the circuit diagram shown in fig. 17, one electrode of the capacitor 10i-1 corresponding to the capacitor 10 of fig. 2 is connected to one electrode (for example, anode) of the solid state light emitting element 20, and the other electrode (for example, cathode) of the solid state light emitting element 20 is connected to the semiconductor switch 30 a. One electrode (e.g., drain electrode) of the semiconductor switch 30a is connected to the solid-state light-emitting element 20, and the other electrode (e.g., source electrode) is connected to the other electrode of the capacitor 10i-1 and the GND wiring.

One electrode of the capacitor 10i-2 is connected to the GND wiring, and the other electrode is connected to the driving element 300. The driving element 300 includes, for example, a semiconductor switch 305 composed of MOSFET, gaNFET or the like, and one electrode (for example, a drain electrode) is electrically connected to the capacitor 10i-2 and the other electrode (for example, a source electrode) is electrically connected to a gate electrode of the semiconductor switch 30a. The semiconductor switch 305 is controlled by a control signal supplied to a control electrode (e.g., a gate electrode), and drives the semiconductor switch 30a.

When the semiconductor switch 30a is driven from the non-conductive state to the conductive state, a current is supplied from the capacitor 10i-2 to the gate electrode of the semiconductor switch 30a for driving the solid-state light-emitting element 20 via the semiconductor switch 305 in the driving element 300, and a current loop b (dotted arrow in fig. 17) is further formed which returns to the capacitor 10i-2 via the parasitic capacitance of the semiconductor switch 30a and the GND wiring. If the parasitic inductance generated by the current loop b is large, the current supplied to the gate electrode of the semiconductor switch 30a is limited, so that the transition time from the non-conductive state to the conductive state becomes long, and a large current cannot be supplied to the semiconductor switch 30a in a short time. In this way, the rising speed of the current of the solid-state light-emitting element 20 is also limited, and it takes a certain time or more to reach the current value required for light emission, and the output of short-pulse light may become difficult.

In modification (10) of the present invention, the driving element 300 that drives the semiconductor switch 30a of the solid state light emitting element 20 is placed on the outer surface of the capacitor for supplying power to the solid state light emitting element 20. Accordingly, the path length of the current loop b for gate driving can be shortened as compared with the case where the driving element is provided outside, and therefore parasitic inductance can be reduced. Further, by forming the capacitor 10i-2 for supplying electric power to the driving element 300 in the capacitor on which the solid state light emitting element 20 or the like is mounted, the path length of the current loop b can be further shortened.

Fig. 18 is a schematic diagram for explaining the structure of a light-emitting device 100p according to a modification (10) of the present invention. Fig. 18 (a) shows a top view of the light emitting device 100p as seen from the outer surface of the capacitor 10I on which the solid state light emitting element 20 is mounted, fig. 18 (b) shows a cross-sectional view on the I-I surface of the light emitting device 100p, fig. 18 (c) shows a cross-sectional view on the II-II surface of the light emitting device 100p, and fig. 18 (d) shows a cross-sectional view on the III-III surface of the light emitting device 100 p. Fig. 19 is a side view of the light emitting device 100 p. Fig. 19 (a) is a side view seen from the arrow AR1 direction of fig. 18 (a), and fig. 19 (b) is a side view seen from the arrow AR2 direction of fig. 18 (a). Note that, in the light-emitting device 100p shown in fig. 18 and 19, the same components as those of the light-emitting device 100 shown in fig. 1 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100p shown in fig. 18 and 19 includes a capacitor 10i, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10i, a semiconductor switch 30a, and a driving element 300. The driving element 300 is electrically connected to an external electrode 320 for power supply, an external electrode 310 for control signal, and an external electrode 312 connected to GND wiring on the outer surface of the capacitor 10 i. The driving element 300 is electrically connected to the semiconductor switch 30a via the gate lead electrode 31. As shown in fig. 19 (a) and (b), external electrodes 310, 312, and 320 are also formed on the side surfaces of the capacitor 10 i.

The capacitor 10i is a power supply capacitor, and is formed of a laminated ceramic capacitor. As described with reference to fig. 17, in the light-emitting device 100p shown in fig. 18, a capacitor 10i-1 for supplying power to the solid-state light-emitting element 20 and a capacitor 10i-2 for supplying power to the driving element 300 are formed. The capacitor 10i-1 is formed in the region RG1 in fig. 18 (a), and as shown in fig. 18 (d), constitutes a laminate in which a plurality of internal electrodes 14 and 15 for obtaining electrostatic capacitance and dielectric ceramic layers 13 are alternately laminated.

On the other hand, the capacitor 10i-2 is formed in the region RG2 in fig. 18 (a), and as shown in fig. 18 (b), a laminate is formed by alternately stacking a plurality of internal electrodes 321 and 322 for obtaining electrostatic capacitance and the dielectric ceramic layer 13. In other words, the internal electrodes 321 (third internal electrodes) and the internal electrodes 322 (fourth internal electrodes) are alternately laminated with the dielectric ceramic layers 13 interposed therebetween to form a laminated body. The internal electrode 321 is led out to the end portion on the external electrode 11 side, and is electrically connected to the external electrode 320 (third external electrode) provided at the end portion thereof. The internal electrode 322 is led out to the end opposite to the internal electrode 321, and is electrically connected to the external electrode 312 (fourth external electrode) connected to the GND wiring.

As shown in fig. 18 (c), there is a region where the internal electrode is not disposed but only the dielectric ceramic layer 13 between the region RG1 where the capacitor 10i-1 is formed and the region RG2 where the capacitor 10i-2 is formed. In other words, the internal electrodes 14 and 15 and the internal electrodes 321 and 322 are not directly connected. That is, in the light emitting device 100p of fig. 18, the internal electrode 15 (second internal electrode) and the internal electrode 322 (fourth internal electrode) corresponding to the electrode on the negative electrode side of the capacitor are insulated from each other, and the internal electrode 14 (first internal electrode) and the internal electrode 321 (third internal electrode) corresponding to the electrode on the positive electrode side of the capacitor are insulated from each other. Although not shown in fig. 18 and 19, the external electrode 12 and the external electrode 312 are connected to a common GND line outside the light-emitting device 100 p. In the light-emitting device 100p, the internal electrode 15 and the internal electrode 322, or the external electrode 12 and the external electrode 312 may be directly connected.

In the light-emitting device 100p shown in fig. 18, as shown in fig. 18 (a) and (b), the current loop b flowing through the driving element 300 is a path of the internal electrode 321, the external electrode 320, the driving element 300, the gate extraction electrode 31, the semiconductor switch 30a, the external electrode 12, the external electrode 312, and the internal electrode 322 of the capacitor 10 i-2. In other words, since the current loop b is formed in the substrate on which the light emitting device 100p is formed, the current loop b can be shortened as compared with a case where the driving element 300 is provided outside the substrate. As shown in fig. 18 (b), the current flowing through the current circuit b is directed to the external electrode 320 and the driving element 300 in the opposite direction to the direction of the current flowing through the internal electrodes 321 and 322, and is directed to the capacitor 10i with a distance h of the outer thickness. As a result, the effect (cancellation effect) of canceling the magnetic fluxes generated by the currents increases, and therefore the parasitic inductance of the current loop b can be reduced.

As described above, in the light emitting device 100p, the parasitic inductance of the current loop b of the current flowing through the driving element 300 is reduced in addition to the current loop a of the driving current of the solid state light emitting element 20, so that the current pulse width can be shortened, and the light output from the solid state light emitting element 20 can be made into a short pulse.

As described above, the light-emitting device 100p according to the modification (10) of the present invention includes the driving element 300 that is mounted on the outer surface of the capacitor 10i and drives the semiconductor switch 30a (switching element). The capacitor 10i includes an internal electrode 321 (third internal electrode) and an internal electrode 322 (fourth internal electrode) provided with the dielectric ceramic layer 13 interposed therebetween, an external electrode 320 (third external electrode) electrically connected to the internal electrode 321, and an external electrode 312 (fourth external electrode) electrically connected to the internal electrode 322. The internal electrode 321 is insulated from the internal electrode 14 (first internal electrode), and the external electrode 312 is electrically connected to the external electrode 12 (second external electrode). The driving element 300 is connected between the external electrode 312 and the external electrode 320. Therefore, the parasitic inductance of the current loop b of the current flowing through the driving element 300 can be reduced, so that the light output from the solid-state light-emitting element 20 can be made into a short pulse.

In fig. 18 and 19, the example in which the capacitor 10i is formed of a laminated ceramic capacitor has been described, but the structure of the capacitor is not limited to this, and a capacitor of a type other than a laminated ceramic capacitor may be used.

Fig. 20 is a schematic diagram for explaining another example of the structure of the light-emitting device according to modification (10) of the present invention, in which a semiconductor capacitor is used as a capacitor, as in embodiment 5. Fig. 20 (a) shows a top view of the light emitting device 100q as seen from the outer surface of the capacitor 10j on which the solid state light emitting element 20 is mounted, fig. 20 (b) shows a cross-sectional view on the I-I plane of the light emitting device 100q, fig. 20 (c) shows a cross-sectional view on the II-II plane of the light emitting device 100q, and fig. 20 (d) shows a cross-sectional view on the III-III plane of the light emitting device 100 q. In the light-emitting device 100q shown in fig. 20, the same components as those of the light-emitting device 100e shown in fig. 8 of embodiment 5 are denoted by the same reference numerals, and detailed description thereof is not repeated.

The light-emitting device 100q shown in fig. 20 includes a capacitor 10j, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10j, a semiconductor switch 30a, and a driving element 300. The driving element 300 is electrically connected to the external electrode 320a for power supply, the external electrode 310a for control signal, and the external electrode 312a connected to the GND wiring on the outer surface of the capacitor 10 j. The driving element 300 is electrically connected to the semiconductor switch 30a via the gate lead electrode 31.

The capacitor 10j is a power supply capacitor, and is formed of a semiconductor capacitor. In the light emitting device 100q shown in fig. 20, a capacitor 10j-1 for supplying power to the solid state light emitting element 20 and a capacitor 10j-2 for supplying power to the driving element 300 are formed. The capacitor 10j-1 is formed in the region RG1a in fig. 20 (a), and the capacitor 10j-2 is formed in the region RG2a in fig. 20 (a).

As described with reference to fig. 8, the capacitor 10j-1 is formed by a semiconductor process. The capacitor 10j-1 is constituted by an n+ layer 15a formed by implanting N-type impurity ions into the silicon substrate 18 at a high concentration, a dielectric layer 13a formed on the surface thereof and made of an inorganic material, for example, by a CVD method, and a polysilicon layer 14a of a conductor formed on the surface of the dielectric layer 13a by a CVD method (fig. 20 c).

The capacitor 10j-2 is also formed by the same semiconductor process, and is composed of an n+ layer 315 formed by implanting N-type impurity ions into the silicon substrate 18, a dielectric layer 313 formed on the surface thereof by a CVD method or the like and made of an inorganic material, and a polysilicon layer 314 of a conductor formed on the surface of the dielectric layer 313 by a CVD method (fig. 20 (b)). The substrate on which the capacitor 10j is formed is described as the silicon substrate 18, but may be a substrate such as a sapphire substrate or a GaAs substrate. The capacitor 10j-1 and the capacitor 10j-2 may be formed using p-type impurity ions instead of n-type impurity ions.

The n+ layer 315 of the capacitor 10j-2 is a low-resistance layer formed by forming a plurality of grooves or a plurality of pillars on the silicon substrate 18 to form a convex-concave shape, and implanting N-type impurity ions into the surface of the formed convex-concave shape at a high concentration. In this way, the capacitance of the capacitor is increased by increasing the area of the dielectric layer sandwiched between the n+ layer and the polysilicon layer.

The polysilicon layer 314 is used as one electrode (third internal electrode) forming the capacitance of the capacitor 10 j-2. The resistivity of one electrode formed of the polysilicon layer 314 is reduced by forming a metal layer 317 on top of the polysilicon layer 314. In addition, if the desired resistivity can be obtained only by the polysilicon layer 314, the metal layer 317 may not be formed. The polysilicon layer 314 having the metal layer 317 formed thereon is electrically connected to the external electrode 320a via the via conductor 316. Although the polysilicon layer 314 forms one electrode (third internal electrode) forming the capacitance of the capacitor 10j-2, the electrode may be formed by a metal layer or the like. The n+ layer 315 is used as another electrode (fourth internal electrode) forming the capacitance of the capacitor 10 j-2. The n+ layer 315 is electrically connected to the external electrode 312a via conductor 318.

As shown in fig. 20 (d), between the region RG1a where the capacitor 10j-1 is formed and the region RG2a where the capacitor 10j-2 is formed, there is a region where the semiconductor capacitor is not formed, but only the silicon substrate 18 is formed. In other words, the polysilicon layer 14a is not directly connected to the polysilicon layer 314, and the n+ layer 15a is not directly connected to the n+ layer 315. That is, in the light emitting device 100q of fig. 20, the n+ layer 15a and the n+ layer 315 corresponding to the electrode on the negative electrode side of the capacitor are insulated from each other, and the polysilicon layer 14a (first internal electrode) and the polysilicon layer 314 (third internal electrode) corresponding to the electrode on the positive electrode side of the capacitor are insulated from each other. Although not shown in fig. 20, the external electrode 12a and the external electrode 312a on the negative electrode side are connected to a common GND wiring outside the light-emitting device 100 q. In the light-emitting device 100q, the n+ layer 15a and the n+ layer 315, or the external electrode 12a and the external electrode 312a may be directly connected.

In the light-emitting device 100q shown in fig. 20, a current loop b flowing through the driving element 300 is a path of the polysilicon layer 314, the metal layer 317, the via conductor 316, the external electrode 320a, the driving element 300, the gate extraction electrode 31, the semiconductor switch 30a, the external electrode 12a, the external electrode 312a, the via conductor 318, and the n+ layer 315 of the capacitor 10j-2, as shown in fig. 20 (a). In the light emitting device 100q, for example, after forming the insulating film 19 having a thickness of 100 μm or less such as silicon oxide or silicon nitride on the metal layer 14b and the metal layer 317, the external electrodes 11a, 12a, 310a, 312a, 320a, the connection electrode 32, and the via conductors 16a, 17a, 316, 318 are formed by a semiconductor process. Therefore, in the light emitting device 100q, the distance between the capacitor 10j-1 and the external electrodes 11a and 12a and the distance between the capacitor 10j-2 and the external electrodes 320a and 312a can be further shortened by the fine processing, and the current loop can be further reduced. Therefore, in the light emitting device 100q, the parasitic inductance of the current loop b of the current flowing through the driving element 300 is reduced in addition to the current loop a of the driving current of the solid state light emitting element 20, so that the current pulse width can be shortened, and the light output from the solid state light emitting element 20 can be made into a short pulse.

(11) In the modification (10), as shown in fig. 17, a configuration in which one electrode of each capacitor is connected to the GND wiring is described. Therefore, in modification (10), the internal electrode 15 and the internal electrode 322 in fig. 18, or the external electrode 12 and the external electrode 312, or the n+ layer 15a and the n+ layer 315 in fig. 19, or the external electrode 12a and the external electrode 312a can be shared with each other.

However, the circuit configuration of the light emitting device is not limited to the configuration shown in fig. 17. In a modification (11) of the present invention, a structure in which a solid state light emitting element, a semiconductor switch, and a driving element are mounted on the outer surface of a capacitor in the same manner as in modification (10), and the capacitor for supplying power to the solid state light emitting element and the capacitor for supplying power to the driving element do not share an electrode with each other will be described.

Fig. 21 is a circuit diagram of a light emitting device 100r according to a modification of the present invention. In the light-emitting device 100r of fig. 21, one electrode of the capacitor 10k-1 that supplies power to the solid-state light-emitting element 20 is connected to a power supply wiring, and the other electrode is connected to one electrode (e.g., cathode) of the solid-state light-emitting element 20. The other electrode (e.g., anode) of the solid-state light-emitting element 20 is connected to the GND wiring. One electrode (e.g., drain electrode) of the semiconductor switch 30a is connected to the power supply wiring, and the other electrode (e.g., source electrode) is connected to the GND wiring.

The circuit for driving the semiconductor switch 30a is the same as that of fig. 17. The power from the capacitor 10k-2 is supplied to the gate electrode of the semiconductor switch 30a through the semiconductor switch 305 in the driving element 300, so that the semiconductor switch 30a is driven. When the semiconductor switch 30a is driven to an on state, a current loop a (solid line arrow in fig. 21) is formed from the electrode on the positive electrode side of the capacitor 10k-1 to the electrode on the positive electrode side of the capacitor 10k-1 via the semiconductor switch 30a and the solid-state light emitting element 20, and the solid-state light emitting element 20 emits light.

As described above, in the circuit configuration of fig. 21, the capacitor 10k-1 and the capacitor 10k-2 do not share the electrode with each other. In such a configuration, the driving element 300 for driving the semiconductor switch 30a of the solid state light emitting element 20 is placed on the outer surface of the capacitor for supplying electric power to the solid state light emitting element 20, and thus the path length of the current loop b for gate driving can be shortened as compared with the case where the driving element is provided outside, so that parasitic inductance can be reduced. Further, by forming the capacitor 10k-2 for supplying power to the driving element 300 in the capacitor on which the solid state light emitting element 20 or the like is mounted, the path length of the current loop b can be further shortened.

Fig. 22 is a schematic diagram for explaining the structure of a light-emitting device 100r according to modification (11) of the present invention. Fig. 22 (a) shows a top view of the light emitting device 100r as seen from the outer surface of the capacitor 10k on which the solid state light emitting element 20 is mounted, fig. 22 (b) shows a cross-sectional view on the I-I plane of the light emitting device 100r, fig. 22 (c) shows a cross-sectional view on the II-II plane of the light emitting device 100r, and fig. 22 (d) shows a cross-sectional view on the III-III plane of the light emitting device 100 r. Fig. 23 is a side view of the light emitting device 100 r. Fig. 23 (a) is a side view seen from the arrow AR1a direction of fig. 22 (a), and fig. 23 (b) is a side view seen from the arrow AR2a direction of fig. 22 (a). In the light-emitting device 100r shown in fig. 22 and 23, the same reference numerals are given to the same components as those of the light-emitting device shown in fig. 1 and 18, and detailed description thereof is not repeated.

The light-emitting device 100r shown in fig. 22 and 23 includes a capacitor 10k, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10k, a semiconductor switch 30a, and a driving element 300. External electrodes 11b, 12b, 32b, 310b, 320b are formed on the outer surface of the capacitor 10 k.

The capacitor 10k is a power supply capacitor, and is formed of a laminated ceramic capacitor. In the light emitting device 100r of fig. 22, a capacitor 10k-1 for supplying power to the solid state light emitting element 20 and a capacitor 10k-2 for supplying power to the driving element 300 are formed. The capacitor 10k-1 is formed in the region RG1b in fig. 22 (a), and is a laminate in which a plurality of internal electrodes 14c and 15c for obtaining capacitance and the dielectric ceramic layer 13 are alternately laminated. The internal electrode 14c (first internal electrode) is led out to one end portion of the capacitor 10k, and is connected to an external electrode 32b (first external electrode) formed at the end portion thereof. The internal electrode 15c (second internal electrode) is led out to the other end of the capacitor 10k, and is connected to the external electrode 11b (second external electrode) connected to the power supply wiring (fig. 22 d).

On the other hand, the capacitor 10k-2 is formed in the region RG2b in fig. 22 (a), and a laminate is formed by alternately laminating a plurality of internal electrodes 321b and 322b for acquiring capacitance and the dielectric ceramic layer 13. The internal electrode 321b (third internal electrode) is led out to the end portion on the external electrode 32b side, and is connected to the external electrode 12b (third external electrode) connected to the GND wiring. The internal electrode 322b (fourth internal electrode) is led out to the end portion on the external electrode 11b side, and is connected to the external electrode 320b (fourth external electrode) formed at the end portion thereof (fig. 22 (b)). As shown in fig. 22 (a), the external electrode 12b (third external electrode) extends from near the center of the region RG1b to the left end of the region RG2 b.

As shown in fig. 22 (c), there is a region having only the dielectric ceramic layer 13 without disposing the internal electrode between the region RG1b where the capacitor 10k-1 is formed and the region RG2b where the capacitor 10k-2 is formed. In other words, the internal electrodes 14c and 15c and the internal electrodes 321b and 322b are not directly connected and are not shared.

The solid state light emitting element 20 is mounted on the external electrode (connection electrode) 32b of the capacitor 10 k. The solid-state light-emitting element 20 is connected to the external electrode 12b through a wiring 21. The semiconductor switch 30a is connected to the external electrode 11b and the external electrode 12 b. Thus, a current loop a is formed in which the semiconductor switch 30a, the external electrode 12b, the wiring 21, the solid-state light-emitting element 20, the external electrode 32b, and the internal electrode 14c are routed from the external electrode 11b (internal electrode 15 c) connected to the power supply wiring. In the present modification (11), the solid-state light-emitting element 20 and the semiconductor switch 30a are connected in series by the external electrode 12b and the wiring 21, and the external electrode 12b and the wiring 21 correspond to conductive portions.

The driving element 300 is electrically connected to the external electrode 320b for power supply, the external electrode 310b for control signal, and the external electrode 12b connected to the GND wiring on the outer surface of the capacitor 10 k. The driving element 300 is electrically connected to the semiconductor switch 30a via the gate lead electrode 31. As shown in fig. 22 (a) and (b), the current loop b flowing through the driving element 300 is a path of the internal electrode 322b, the external electrode 320b, the driving element 300, the gate electrode 31, the semiconductor switch 30a, the external electrode 12b, and the internal electrode 321b of the capacitor 10 k-2. In other words, since the current loop b is formed in the substrate on which the light emitting device 100r is formed, as in modification (10), the current loop b can be shortened as compared with the case where the driving element 300 is provided outside the substrate. In the present modification (11), the direction of the current flowing from the external electrode 320b to the external electrode 12b via the driving element 300 is opposite to and faces the direction of the current flowing through the internal electrodes 321b and 322b, and the directions are opposite to each other by the distance h of the outer thickness of the capacitor 10 k. As a result, the effect (cancellation effect) of canceling the magnetic fluxes generated by the currents increases, and therefore the parasitic inductance of the current loop b can be reduced.

As described above, in the structure of the light emitting device 100r, the parasitic inductance of the current loop b of the current flowing through the driving element 300 is reduced in addition to the current loop a of the driving current of the solid state light emitting element 20, so that the current pulse width can be shortened, and the light output from the solid state light emitting element 20 can be made into a short pulse.

As described above, the light-emitting device 100r according to modification (11) of the present invention includes the driving element 300 that is mounted on the outer surface of the capacitor 10k and drives the semiconductor switch 30a (switching element). The capacitor 10k includes an internal electrode 321b (third internal electrode) and an internal electrode 322b (fourth internal electrode) provided with the dielectric ceramic layer 13 interposed therebetween, an external electrode 12b (third external electrode) electrically connected to the internal electrode 321b, and an external electrode 320b (fourth external electrode) electrically connected to the internal electrode 322 b. Further, the internal electrode 321b is insulated from the internal electrode 14c (first internal electrode). The driving element 300 is connected between the external electrode 320b (fourth external electrode) and the external electrode 12b (third external electrode). Therefore, the parasitic inductance of the current loop b of the current flowing through the driving element 300 can be reduced, so that the light output from the solid-state light-emitting element 20 can be made into a short pulse.

Fig. 24 is a schematic diagram for explaining another example of the structure of the light-emitting device according to modification (11) of the present invention, and is a structure using a semiconductor capacitor as a capacitor, similar to fig. 20 of modification (10). Fig. 24 (a) shows a top view of the light emitting device 100s as seen from the outer surface of the capacitor 10m on which the solid state light emitting element 20 is mounted, fig. 24 (b) shows a cross-sectional view on the I-I plane of the light emitting device 100s, fig. 24 (c) shows a cross-sectional view on the II-II plane of the light emitting device 100s, and fig. 24 (d) shows a cross-sectional view on the III-III plane of the light emitting device 100 s. The light-emitting device 100s shown in fig. 22 includes a capacitor 10m, a solid-state light-emitting element 20 mounted on the outer surface of the capacitor 10m, a semiconductor switch 30a, and a driving element 300.

The capacitor 10m is a power supply capacitor, and is formed of a semiconductor capacitor. In the light-emitting device 100s shown in fig. 24, a capacitor 10m-1 for supplying power to the solid state light-emitting element 20 and a capacitor 10m-2 for supplying power to the driving element 300 are formed. The capacitor 10m-1 is formed in the region RG1c in fig. 24 (a), and the capacitor 10m-2 is formed in the region RG2c in fig. 24 (a).

The capacitor 10m-1 is formed by a semiconductor process, as in fig. 20. The capacitor 10m-1 is constituted by an n+ layer 15d formed by implanting N-type impurity ions into the silicon substrate 18 at a high concentration, a dielectric layer 13c formed on the surface thereof and made of an inorganic material, for example, by a CVD method, and a polysilicon layer 14d of a conductor formed on the surface of the dielectric layer 13c by a CVD method (fig. 24 c).

By forming the metal layer 14e on the upper layer of the polysilicon layer 14d, the resistivity of one electrode formed of the polysilicon layer 14d is reduced. Further, if the desired resistivity can be obtained only by the polysilicon layer 14d, the metal layer 14e may not be formed. The polysilicon layer 14d having the metal layer 14e formed thereon is electrically connected to the external electrode 32c via the via conductor 16 c. The n+ layer 15d is electrically connected to the external electrode 11c connected to the power supply wiring via the via conductor 17 c.

The capacitor 10m-2 is also formed by the semiconductor process in the same manner, and is composed of an n+ layer 315c formed by implanting N-type impurity ions into the silicon substrate 18, a dielectric layer 313c formed on the surface thereof by a CVD method or the like and made of an inorganic material, and a polysilicon layer 314c of a conductor formed on the surface of the dielectric layer 313 by a CVD method (fig. 24 b). The capacitor 10m-1 and the capacitor 10m-2 may be formed using p-type impurity ions instead of n-type impurity ions.

The n+ layer 315c of the capacitor 10m-2 is a low-resistance layer formed by forming a plurality of grooves or a plurality of pillars on the silicon substrate 18 to form a convex-concave shape, and implanting N-type impurity ions into the surface of the formed convex-concave shape at a high concentration.

The polysilicon layer 314c is used as one electrode (third internal electrode) forming the capacitance of the capacitor 10 m-2. By forming the metal layer 317c on the upper layer of the polysilicon layer 314c, the resistivity of one electrode formed of the polysilicon layer 314c is reduced. In addition, if the desired resistivity can be obtained only by the polysilicon layer 314c, the metal layer 317c may not be formed. The polysilicon layer 314c having the metal layer 317c formed on the upper layer is electrically connected to the external electrode 12c connected to the GND wiring through the via hole conductor 318c (fig. 24 (d)).

One electrode (third internal electrode) forming the capacitance of the capacitor 10m-2 is formed by the polysilicon layer 314c, but the electrode may be formed by a metal layer or the like. The n+ layer 315c is used as the other electrode (fourth internal electrode) forming the capacitance of the capacitor 10 m-2. The n+ layer 315c is electrically connected to the external electrode 320c via the via conductor 316 c.

The solid state light emitting element 20 is mounted on the external electrode 32c. In the solid-state light-emitting element 20, one electrode (e.g., a cathode) is connected to the external electrode 32c, and the other electrode (e.g., an anode) is connected to the external electrode 12c via the wiring 21.

In the semiconductor switch 30a, one electrode (for example, a drain electrode) is connected to the external electrode 11c, and the other electrode (for example, a source electrode) is connected to the external electrode 12 c.

The driving element 300 is electrically connected to the external electrode 320c for power supply, the external electrode 310c for control signal, and the external electrode 12c connected to the GND wiring on the outer surface of the capacitor 10 m. The driving element 300 is electrically connected to the semiconductor switch 30a via the gate lead electrode 31.

In the light-emitting device 100s shown in fig. 24, a current loop b flowing through the driving element 300 is a path of the n+ layer 315c, the via conductor 316c, the external electrode 320c, the driving element 300, the gate extraction electrode 31, the semiconductor switch 30a, the external electrode 12c, the via conductor 318c, the metal layer 317c, and the polysilicon layer 314c of the capacitor 10m-2, as shown in fig. 24. In the light emitting device 100s, the current loop b can be reduced. Therefore, since the parasitic inductance of the current loop b of the current flowing through the driving element 300 is also reduced, the current pulse width can be shortened, and the light output from the solid state light emitting element 20 can be made into a shorter pulse.

The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims, rather than by the description above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Description of the reference numerals

10 … capacitor; 11. 12, 310, 312, 320, … external electrodes; 13 … dielectric ceramic layer; 13a, 13c, 313 … dielectric layers; 14. 15, 321, 322, … inner electrodes; 14a, 14c, 314 … polysilicon layers; 14b, 317 … metal layers; 15a, 15c, 315 … n+ layers; 16. 17, 316, 318 … via conductors; 18 … silicon substrate; 19 … oxide film; 20 … solid state light emitting element; 21. 33, 41 … wiring; 22 … light emitting part; 23 … metal plate; 30. 30a, 305 … semiconductor switches; 31 … gate lead-out electrode; 32 … to the electrodes; 40 … clamp diode; 50 … light receiving element; 60 … passivation layer; 100 … light emitting device; 300 … drive element.

Claims

1. A light emitting device is provided with:

a capacitor, comprising: a dielectric layer; a first internal electrode and a second internal electrode provided with the dielectric layer interposed therebetween; a first external electrode electrically connected to the first internal electrode; and a second external electrode electrically connected to the second internal electrode;

one or more solid-state light-emitting elements that emit light by being supplied with power from the capacitor; and

a switching element for controlling the power supply from the capacitor to the solid state light emitting element,

The solid state light emitting element is placed on an outer surface of the capacitor, and the switching element is placed on an outer surface of the capacitor or is provided inside the capacitor, and the capacitor has a conductive portion for connecting the solid state light emitting element and the switching element in series between the first external electrode and the second external electrode.

2. The light-emitting device of claim 1, wherein,

the conductive part has a connection electrode provided on an outer surface of the capacitor.

3. The light-emitting device according to claim 1 or 2, wherein,

the capacitor is a semiconductor capacitor including the dielectric layer, and the first internal electrode and the second internal electrode disposed with the dielectric layer interposed therebetween on a semiconductor substrate.

4. The light-emitting device according to claim 3, wherein,

the semiconductor capacitor has an insulating film of 10 μm or less on an outer surface thereof, and has a connection electrode provided on the outer surface of the capacitor with the insulating film interposed therebetween.

5. The light-emitting device according to claim 1 or 2, wherein,

the capacitor includes:

a first via conductor electrically connected to the first internal electrode and the solid-state light-emitting element; and

A second via conductor electrically connected to the second internal electrode and the switching element,

the first via conductor and the second via conductor are electrically connected to an external electrode of the capacitor.

6. The light-emitting device of claim 5, wherein,

the first via conductor is provided at a position connected to one end of the solid state light emitting element mounted on the outer surface of the capacitor,

the second via conductor is provided at a position connected to one end of the switching element mounted on the outer surface of the capacitor.

7. The light-emitting device according to claim 1 or 2, wherein,

the solid state light emitting element can emit light in a horizontal direction with respect to the outer surface of the capacitor,

the switching element is placed on an outer surface of the capacitor so as to avoid a light path of light emitted from the solid state light emitting element.

8. The light-emitting device of claim 7, wherein,

the switching element is disposed so as to be offset in a horizontal direction from the solid-state light-emitting element on an outer surface of the capacitor.

9. The light-emitting device of claim 7, wherein,

the switching element is disposed so as to be offset from the solid-state light-emitting element in a vertical direction on an outer surface of the capacitor.

10. The light-emitting device of claim 7, wherein,

the solid state light emitting device further includes a light receiving element provided on an optical path of the light emitted from the solid state light emitting element and receiving the light from the solid state light emitting element.

11. The light-emitting device according to claim 3, wherein,

the dielectric layer of the semiconductor capacitor is formed in a direction perpendicular to an outer surface of the capacitor on which the solid state light emitting element and the switching element are mounted.

12. The light-emitting device of claim 11, wherein,

the semiconductor capacitor has a convex portion of the semiconductor substrate immediately below a position where the solid state light emitting element and the switching element are mounted, and the convex portion of the semiconductor substrate is located laterally to a capacitance forming portion formed by the dielectric layer and the first internal electrode and the second internal electrode provided with the dielectric layer interposed therebetween.

13. The light-emitting device of claim 11, wherein,

the semiconductor capacitor includes:

and a second via conductor electrically connected to the second internal electrode and the switching element.

14. The light-emitting device of claim 13, wherein,

the first via conductor and the second via conductor are electrically connected to a third via conductor, respectively, which reaches a surface opposite to an outer surface of the semiconductor capacitor on which the solid state light emitting element and the switching element are mounted.

15. The light emitting device of claim 14, wherein,

the third via conductor is made of a material having higher thermal conductivity than the semiconductor substrate.

16. The light-emitting device according to claim 3, wherein,

the semiconductor substrate is silicon.

17. The light-emitting device of claim 1, wherein,

and a driving element mounted on an outer surface of the capacitor and configured to drive the switching element,

the capacitor further comprises:

a third internal electrode and a fourth internal electrode provided so as to sandwich the dielectric layer;

a third external electrode electrically connected to the third internal electrode; and

a fourth external electrode electrically connected to the fourth internal electrode,

the third internal electrode is insulated from the first internal electrode,

the driving element is connected between the third external electrode and the fourth external electrode.

18. The light emitting apparatus of claim 17 wherein,

the fourth external electrode is electrically connected to the second external electrode.

19. A capacitor including a dielectric layer, and first and second internal electrodes provided across the dielectric layer, the capacitor comprising:

a mounting portion for mounting one or more solid-state light-emitting elements that emit light by supplying power from the capacitor on an outer surface of the capacitor, and for mounting a switching element that controls power supply from the capacitor to the solid-state light-emitting elements on the outer surface of the capacitor or in the capacitor; and

and a conductive portion provided in the mounting portion and connecting the capacitor and the switching element in series.